all eyes and sight stories

When the blues keep you awake

50443248 — Thu, 19 Jul 2007 12:50:17 -0400

Your eyes do more than see.
Researchers at Harvard Medical School demonstrated this by showing that your eyes are part of a light reception system that can keep you alert when sleep starts to fog your brain. When the researchers exposed people to blue light at night, this system immediately increased their alertness and performance on tests.

Bacterium present in eyes with 'wet' age-related macular degeneration

70652986 — Mon, 26 Mar 2007 06:23:08 -0400

Age-related macular degeneration (AMD) is the leading cause of blindness in Americans over the age of 55. The majority of vision loss is due to neovascular AMD, the advanced form of the disease characterized by the formation of blood vessels in the macula, the center part of the eye's retina. These blood vessels often leak, thus giving neovascular AMD the name of "wet" AMD.

Researchers at the Massachusetts Eye and Ear Infirmary (MEEI) have found that chlamydia pneumoniae, a bacterium linked to heart disease and capable of causing chronic inflammation, was present in the diseased eye tissue of five out of nine people with "wet" AMD. However, it was not found in the eyes of more than 20 individuals without AMD, providing more evidence that this disease may be caused by inflammation. The study is described in the November 2005 issue of Graefe's Archive for Clinical and Experimental Ophthalmology.

"The paper showed that C. pneumoniae is capable of modifying the function of important cell types involved in regulating normal eye function," said lead author Murat Kalayoglu, MD, PhD. "We found that C. pneumoniae infection led to increased production of vascular endothelial growth factor (VEGF), the key protein involved in wet AMD. That C. pneumoniae infection of human eye cell types increases VEGF production is therefore significant and could explain in part why VEGF levels are increased in many people with wet AMD." Kalayoglu is a Harvard Medical School research fellow in ophthalmology at MEEI.

Dietary fat intake linked to dry eye syndrome in women

70652986 — Mon, 26 Mar 2007 05:40:54 -0400

Dry eye syndrome is characterized by a decline in the quality or quantity of tears that normally bathe the eye to keep it moist and functioning well. The condition causes symptoms such as pain, irritation, dryness, and/or a sandy or gritty sensation. If untreated, severe dry eye syndrome can eventually lead to scarring or ulceration of the cornea, and loss of vision. Victims can experience symptoms so constant and severe that reading, driving, working and participating in other vision-related activities of daily life are difficult or impossible.

According to study lead author Biljana Miljanovic, MD, of the Divisions of Preventive Medicine and Aging at Brigham and Women's Hospital, "Dry eye syndrome impacts quality of life, productivity and safety for millions of people. Unfortunately, there is little advice clinicians can offer about its prevention. Our study set out to examine how changing dietary habits in America, primarily a shift in the balance of essential fatty acids we are consuming, may be associated with onset of this eye disease. We found that a high intake of omega 3 fatty acids, often referred to as a 'good' fat, commonly found in fish and walnuts, is associated with a protective effect. Conversely, a higher ratio of omega 6, a fat found in many cooking and salad oils and animal meats, compared to omega 3 in the diet, may increase the risk of dry eye syndrome."

Researchers found that tuna consumption reduced the risk of dry eye syndrome. Women who reported eating at least five servings of tuna per week had a 68 percent reduced risk of dry eye syndrome compared to women who consumed one serving per week. Other fish types that have lower levels of omega 3 fatty acids did not appear to protect against dry eye syndrome.

Study shows new compound may reduce risk of vision loss in patients with diabetes

70652986 — Mon, 26 Mar 2007 06:21:31 -0400

The PKC-Diabetic Retinopathy Study (DRS) was designed to evaluate the safety and effect of an oral treatment, RBX, on retinopathy progression or visual loss in patients with moderately severe to very severe nonproliferative diabetic retinopathy. In the study, patients with type 1 or type 2 diabetes received either RBX or a placebo over three to four years. The study measured the effect of three orally administered doses of RBX on progression of diabetic retinopathy, moderate visual loss and sustained moderate visual loss. The study was conducted at Joslin Diabetes Center and assorted national and international medical centers.

The oral treatment RBX inhibits the activity of the enzyme protein kinase C. PKC is essential to the normal production of energy in the body, but one form of the enzyme - PKC-beta - has been linked to diabetic complications of the eye and other parts of the body. Thus RBX was designed to be selective for the single PKC-beta isoform.

"Our results demonstrate that although RBX did not prevent progression to proliferative diabetic retinopathy, it may reduce the risk of moderate vision loss caused by macular edema," said study chairman Lloyd Paul Aiello, M.D., Ph.D., head of Joslin's section on eye research, director of Joslin's Beetham Eye Institute and associate professor of ophthalmology at Harvard Medical School.

Lazy eyes aid artists, biologist says

50443248 — Tue, 24 Jul 2007 14:56:00 -0400

Margaret Livingstone found herself in a small room at the Louvre museum in Paris with four self-portraits by Rembrandt. She noticed something strange. The eyes of the great 17th century artist are crooked. The eye on the right side of the painting looks straight at the viewer, but the other eye looks off to the side. Because these are self-portraits, Rembrandt did them by looking in the mirror, so his left eye would be the one looking off to the side.
This view led the Harvard Medical School professor of neurobiology to the conclusion that Rembrandt was stereoblind, he could not see three dimensions well. His world was flat. She and her colleague, Bevil Conway, subsequently checked a total of 24 self-portraits and confirmed that conclusion.

Seeing seeing in action

50443248 — Wed, 25 Jul 2007 14:07:29 -0400

Harvard Medical School researchers are seeing what seeing does to the brains of animals and making images that show for the first time single brain cells working together.

The work, by Professor of Neurobiology Clay Reid and colleagues from Harvard Medical School, combines existing imaging techniques to create high-resolution movies of the working brain.

Previous techniques have been able to measure the firing of single brain cells, but have done so blindly. Reid said the old technology is like walking through a cocktail party with one's eyes closed and hearing conversations but never being exactly sure who's speaking. The new techniques take those blinders off, allowing researchers to even make time-lapse images of groups of nerve cells firing in response to visual stimulation.

Research in brief

50443248 — Wed, 25 Jul 2007 14:44:11 -0400

Optic nerve regenerated for first time, brings hope to glaucoma sufferers

For the first time, scientists have regenerated a damaged optic nerve - from the eye to the brain. This achievement, which occurred in laboratory mice and is described in the March 1 issue of the Journal of Cell Science, holds great promise for victims of diseases that destroy the optic nerve, and for sufferers of central nervous system injuries.

"For us, this is a dream becoming reality," says Dong Feng Chen, lead author of the study, assistant scientist at Schepens Eye Research Institute and an assistant professor of ophthalmology at Harvard Medical School. "This is the closest science has come to regenerating so many nerve fibers over a long distance to reach their targets and to repair a nerve previously considered irreparably damaged."

Full story, http://www.theschepens.org/df_chenrelease.htm

Mechanical tension helps shape lung development

Organ development in the embryo requires precise coordination and timing of cell growth in three-dimensional space to produce the correct anatomic form and shape. Researchers at Children's Hospital Boston, led by Donald Ingber, a senior researcher in the Vascular Biology Program, have demonstrated that the process of budding and branching in the developing lung is driven by mechanical forces generated within individual cells. They have also identified a possible biochemical target for intervention. These insights could lead to new ways to prevent, minimize, or even correct diseases and anomalies of the lungs, which are common in premature newborns.

Full story, http://www.childrenshospital.org/cfapps/CHdeptPagePressDisplay.cfm?Dept=... or visit http://labworks.hms.harvard.edu

Accumulated low-level lead exposure can lead to cataract development in men

70652986 — Mon, 26 Mar 2007 06:20:29 -0400

According to lead author Debra A. Schaumberg, Sc.D., O.D., M.P.H. of BWH, "This research suggests that reduction of lead exposure throughout a man's lifetime should help reduce his chances of developing cataracts and of requiring cataract surgery. By preventing or delaying the onset of this condition, many instances of blindness worldwide could be prevented."

Drugs are effective against eye disease

70652986 — Mon, 26 Mar 2007 05:33:15 -0400

Results of two large international clinical trials have shown positive results using Macugen, an experimental treatment that targets the abnormal blood vessels found in the "wet" form of macular degeneration. The results, described in November 2003 at the American Academy of Ophthalmology's annual meeting in Anaheim, Calif., demonstrated the drug's ability to decrease vision loss. The Massachusetts Eye and Ear Infirmary (MEEI) in Boston participated in the clinical trials. In addition, researchers and physicians at MEEI - Tony Adamis (formerly of MEEI), Evangelos Gragoudas, and Joan Miller - were among the first to study the role of vascular endothelial growth factor (VEGF), which causes abnormal blood vessel growth in eye disease. Their experimental studies showed that levels of VEGF protein were increased in eyes that developed abnormal new blood vessels, and that VEGF-blocking drugs were able to prevent the growth of these abnormal blood vessels. Others, including Harvard's Lloyd Paul Aiello of the Joslin Diabetes Center and Lois Smith of Children's Hospital, corroborated the importance of VEGF in neovascular eye disease. These studies formed the basis for the drug development and clinical trials of anti-VEGF therapies, including Macugen, and demonstrate the importance of translational research, in order to transform scientific discoveries into new therapies for patients.

Hormone replacement therapy may lower degenerative eye disease risk in postmenopausal women

70652986 — Mon, 26 Mar 2007 05:26:32 -0400

ARM is a degenerative eye disease that affects the macula, which is responsible for central vision, which is necessary for reading, driving and recognizing people's faces. Advanced ARM is the leading cause of irreversible blindness among elderly individuals worldwide. Approximately 1.7 million people have decreased vision due to ARM, and 200,000 people develop advanced ARM with visual loss each year. A study published in the December 2002 issue of the American Journal of Ophthalmology showed that postmenopausal hormone therapy may reduce the risk of having advanced ARM among women with signs of maculopathy. "Decisions regarding postmenopausal hormone therapies are becoming increasingly complex, and it is important to evaluate their effects, including testing their relationship to eye diseases of aging," said lead author Johanna M. Seddon, director of the Epidemiology Unit at the Massachusetts Eye and Ear Infirmary and associate professor of ophthalmology at Harvard Medical School.

Science illuminates art

70652986 — Mon, 26 Mar 2007 05:21:10 -0400

Monet and other painters exploited the parallel visual processing of color and brightness. A sunset seems to shimmer, a field of poppies seems to wave, and a river seems to flow when there is a disconnect between the color and luminance pathways, according to a book, Vision and Art: The Biology of Seeing, by Margaret Livingstone, Harvard Medical School professor of neurobiology. Art implies a personal, unanalyzable creative power, but Livingstone finds plenty to analyze about how various works of art -- and Impressionist paintings in particular -- reflect different properties of the visual system. "Art depends ultimately on our brains," says colleague David Hubel, who has worked with Livingstone for 27 years and wrote the foreword for her book.

Brain may have two minds of its own

70652986 — Mon, 26 Mar 2007 05:20:53 -0400

Human brains are split into two hemispheres, which much research has shown can represent two states of mind. Due to some strange, unexplained quirk of evolution, scenes seen through the visual field of the right eye register as nerve impulses in the left half of the brain and vice versa. Goggles that limit vision to what the outer half of the right eye sees register images in the left hemisphere. Unexpectedly, such a view seems to alter the emotional views of some people. Harvard researcher Fredric Schiffer has shown that some patients with depression and post-traumatic stress syndrome see the world differently, depending on whether they look at it through the outer half of their left or right eye.

Researchers eye earliest triggers of age-related macular degeneration

70652986 — Mon, 26 Mar 2007 05:18:53 -0400

Age-related macular degeneration is the leading cause of blindness for Americans over 60 years of age. It affects more than 14 million people. But how it attacks the macula, the center of the retina, is a controversial question. The macula is where the cones -- the color and light sensing cells of the eye -- reside. Macular degeneration involves the decreased functioning of the cones. Some researchers have long thought that the demise of the cones involves the inability of the cones to regenerate a necessary pigment. But a more complicated picture is emerging because of the work of Harvard researchers. Schepens Eye Research Institute's Ann Elsner, Stephen Burns, and John Weiter have been studying people with early stages of disease and found that the cones' ability to collect light is impaired even when their ability to regenerate pigment is about normal. The researchers, whose report appears in the January 2002 Journal of the Optical Society of America, suggest that the initial problem lies not in the cones' ability to recycle their light-processing pigment but in their ability to physically capture light in the first place. The findings could be used to prevent future generations from suffering macular degeneration's damage.

Comprehensive set of vision genes discovered

70652986 — Mon, 26 Mar 2007 05:16:45 -0400

Using a computer program that compares bits of genetic material taken from tissue in the retinas of mice against records in a huge genetic data base from the mouse and human genome project, Harvard Medical School researchers identified approximately 300 photoreceptor genes. That is five times the number of retinal genes that were previously known. Two hundred sixty four of these were newly identified genes. Of these, 241 had homologs, or counterparts, in humans. The identification of the retinal genes means that researchers have discovered nearly all the genes responsible for vision, which could help in diagnosing and treating blinding diseases. The discovery could also lead to new methods for preserving and restoring the vision of those affected. "The more we know about how the genes work, the better we will be able to find ways to treat, and possibly, prevent disease," said Connie Cepko, Harvard Medical School professor of genetics and senior author of the study. The research was reported in the November 30, 2001, Cell. The research was funded through the Foundation for Retinal Research and the National Institutes of Health.

Snack foods may increase risk of age-related sight loss

70652986 — Mon, 26 Mar 2007 05:15:26 -0400

Macular degeneration results from the malfunctioning or loss of function of photo-sensitive cells in the retina. According to the Macular Degeneration Foundation, more than 13 million people in the United States are affected; a new case of adult macular degeneration is diagnosed in the U.S. every three minutes. A study in the August 2001 issue of the Archives of Ophthalmology found that a higher intake of specific types of fat, including vegetable, monounsaturated and polyunsaturated fats, may be associated with a greater risk for advanced adult macular degeneration.